Probing effects of pH change on dynamic response of Claudin-2 mediated adhesion using single molecule force spectroscopy
- Bioinformatics Institute, Agency for Science, Technology and Research (A-STAR), 30 Biopolis Street, 07-01 Matrix, Singapore 138671 (Singapore)
- Division of Bioengineering and Department of Mechanical Engineering, 9 Engineering Drive 1, National University of Singapore, Singapore 117576 (Singapore)
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A-STAR), 61 Biopolis Drive, Proteos, Singapore 138673 (Singapore)
Claudins belong to a large family of transmembrane proteins that localize at tight junctions (TJs) where they play a central role in regulating paracellular transport of solutes and nutrients across epithelial monolayers. Their ability to regulate the paracellular pathway is highly influenced by changes in extracellular pH. However, the effect of changes in pH on the strength and kinetics of claudin mediated adhesion is poorly understood. Using atomic force microscopy, we characterized the kinetic properties of homophilic trans-interactions between full length recombinant GST tagged Claudin-2 (Cldn2) under different pH conditions. In measurements covering three orders of magnitude change in force loading rate of 10{sup 2}-10{sup 4} pN/s, the Cldn2/Cldn2 force spectrum (i.e., unbinding force versus loading rate) revealed a fast and a slow loading regime that characterized a steep inner activation barrier and a wide outer activation barrier throughout pH range of 4.5-8. Comparing to the neutral condition (pH 6.9), differences in the inner energy barriers for the dissociation of Cldn2/Cldn2 mediated interactions at acidic and alkaline environments were found to be < 0.65 k{sub B}T, which is much lower than the outer dissociation energy barrier (> 1.37 k{sub B}T). The relatively stable interaction of Cldn2/Cldn2 in neutral environment suggests that electrostatic interactions may contribute to the overall adhesion strength of Cldn2 interactions. Our results provide an insight into the changes in the inter-molecular forces and adhesion kinetics of Cldn2 mediated interactions in acidic, neutral and alkaline environments.
- OSTI ID:
- 21128149
- Journal Information:
- Experimental Cell Research, Vol. 314, Issue 14; Other Information: DOI: 10.1016/j.yexcr.2008.05.015; PII: S0014-4827(08)00215-2; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0014-4827
- Country of Publication:
- United States
- Language:
- English
Similar Records
Glycogen Synthase Kinase 3 (GSK-3) influences epithelial barrier function by regulating Occludin, Claudin-1 and E-cadherin expression
Structural basis for Clostridium perfringens enterotoxin targeting of claudins at tight junctions in mammalian gut